SEATTLE — One lane in each direction of State Route 99 across the Aurora Bridge is closed until Nov. 10 for emergency repair work.

Crews will make emergency repairs on the bridge after inspectors found deterioration of steel. 

Inspectors identified a number of issues they were concerned about during a 32-hour routine inspection of the 1930's era bridge in September. During the follow-up inspection this past weekend, crews found corrosion and several cracks on a steel stringer.

Stringers run the length of the bridge and support the weight of traffic. 

Mark Gaines, state bridge inspector for Washington State Department of Transportation, said crews noticed about a half-inch collapse of the outside stringer, which promoted the lane closure.

Gaines said bridges are built to last at least 75 years. The Aurora Bridge is almost 90 years old. 

State Engineering Manager Ed Kane says the repairs will cost between $200,000 to $500,000. Exactly how much work is needed won't be known until workers can investigate further. 

Drivers should plan for delays, especially during the morning and afternoon commutes if traveling toward downtown Seattle through Fremont and Wallingford.